Folding walker having latching mechanism

ABSTRACT

A foldable walker includes first and second side frames, each frame having a front leg, rear leg, and an arm connecting the front leg and rear leg. A detent is urged by a spring or spring clip resiliently into engagement with a sleeve and a front leg. The sleeve surrounds a portion of the front leg and allows rotation and displacement of the leg relative to the first sleeve when the detent is disengaged. Alternately, a recess on the sleeve engages a pin, thereby preventing rotation of the leg relative to the sleeve. The detent is disengaged by a cable, or the pin is disengaged from the recess by depressing a lateral arm that is fixed to the sleeve.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to the field of devices for assisting disabled persons in walking. More particularly it pertains to such devices having ability to be folded compactly.

[0003] 2. Description of the Prior Art

[0004] U.S. Pat. No. 5,579,793 describes a foldable device having a button connected to levers, which rotate to move rods. When the rods are moved, pawls rotate out of their normal engagement with bosses carried on a first pair of legs. Those legs and a second pair of legs rotate with respect to a housing, and the button remains depressed until the first pair of legs is locked again by engagement of the pawls with the bosses. This action provides a visual indication to the user that the first pair of legs is locked. U.S. Pat. No. 5,275,187 describes a folding mechanism in which left and right latches release and lock side frames in response to manual movement of a single actuator. When the latches are released, the side frames pivot to a closed or folded position, where the side frames are maintain locked by the latches. The latches must be released manually by the actuator to allow the slide frames to pivot to the use position.

[0005] U.S. Pat. No. 5,979,476 describes another latching mechanism, in which latches hold the side frames in an open position or an intermediate position between the open and folded positions. When the latches are released, the side frames pivot with to the respect a cross bar. The device described in U.S. Pat. No. 5,433,235 includes a pair of locking members supported on a cross brace and engaged to a side frame. Each locking member includes a spring-biased pin, which locks the side frame against movement relative to the cross brace.

[0006] In another form of such devices known from the prior art, right-hand and left-hand latches are operated manually by the user. U.S. Pat. No. 5,201,333 discloses a device having plates fixed to a cross member and mounted on a front frame. Detents, actuated by lever releases mounted on the side frames, engage fixed plate when the side frames are in the open position and disengage the fixed plates to permit the frame to be folded. The device of U.S. Pat. No. 5,862,825 includes a pair of levers pivotally mounted to the side frame, adapted to lift a pair of skewed surfaces on the front frame out of engagement with skewed surfaces on the pair of side frames and into notches. When this is done the side frames are free to pivot inwardly to close the device.

[0007] The locking assembly of U.S. Pat. No. 5,529,425 includes a housing secured to each of the front legs of the side frames, and a locking pin extending through a first bore, the locking pin being moveable and including an end that extends into a hole of a lock plate connected to a sleeve of the cross brace to actuating levers. Each lever is pivotally connected to the housing and includes a handle, which when depressed causes the lever to rotate about a pivot and to raise the lock pin from the lock plate hole, thereby allowing the side frame to rotate with respect to the cross brace.

SUMMARY OF THE INVENTION

[0008] In realizing these and other advantages and objectives of the invention a folding walker according to the present invention for assisting disabled persons includes first and second side frames, each frame having a front leg, rear leg, and an arm connecting the front leg and rear leg, a lateral arm interconnecting the first and second side frames, and fixed against rotation relative to the front legs; a first sleeve fixed to the lateral arm, surrounding a portion of a first leg of a first member of a group consisting of the first side frame and second side frame, permitting rotary movement of said first leg relative thereto; and first spring means for urging said first front leg and said first sleeve into releasable mutual engagement, said engagement preventing rotary movement of said first leg relative to the first sleeve. The walker includes a second sleeve fixed to the lateral arm, surrounding a portion of a second leg of the second member of said group, permitting rotary movement of said second leg relative thereto; and second spring means for urging said second front leg and said second sleeve into releasable mutual engagement, said engagement preventing rotary movement of said second leg relative to the second sleeve.

[0009] In another embodiment a pin, carried on and extending from a front leg, is urged by a spring into engagement with a sleeve, which surrounds a portion of the front leg and allows rotation and displacement of the leg relative to the first sleeve. A recess on the sleeve releasably engages the pin, preventing movement of the leg relative to the sleeve while so engaged and permitting movement of the leg relative to the sleeve when disengaged.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is an isometric side view of a device according to this invention in the open position.

[0011] FIG. 2 is an isometric view showing a side frame passing through a sleeve supported on a cross member.

[0012] FIG. 3 is an isometric view of the detail located at the upper end of each sleeve.

[0013] FIG. 4 is a top view of a sleeve showing transverse recesses adapted to engage a pin.

[0014] FIG. 5 shows a device according to this invention in an upright position for use to assist in climbing stairs.

[0015] FIG. 6 shows a device folded for storage.

[0016] FIG. 7 is a cross section of an alternative embodiment taken at a vertical plane through a front leg at the upper end of a sleeve.

[0017] FIG. 8 is a cross section similar to that of FIG. 7, but of another embodiment.

[0018] FIG. 9 is a cross section taken at plane 9-9 of FIG. 8.

[0019] FIG. 10 is an isometric side view of a front leg at the upper end of a sleeve showing yet another embodiment.

DESCRIPTION OF THE PREFERRED ENBODIMENT

[0020] Referring first to FIG. 1, a walker 10 according to the present invention includes left-hand side frame and a right-hand side frame, each frame preferably formed of tubular metal stock. The left-hand side frame includes a front leg 12, rear leg 14, and an arm 16 extending between the front leg and rear leg and formed integrally with those legs. A bracket 18, surrounding the outer surface of the forward leg, is clamped to the front leg and joined to a forward portion the outer surface of intermediate longitudinal arm 20 by a pin or bolt 22, which extends through the bracket 18 and arm 20. A weld 24 joins the rear of arm 20 to the rear leg 14. One stopper cap 26, 28 covers the lower end of the front leg 12 and another cap 28 covers the lower end of rear leg 14. Each cap is preferably formed of rubber or an elastomeric material.

[0021] A sleeve 30 having a somewhat larger inside diameter than the outer diameter of front leg 12 is moveably supported on the front leg above the location of bracket 18 and extends upward to the location of the upper lateral arm 32, which is connected to the sleeve 30 at the right-hand lateral end, preferably by a weld 34.

[0022] The right-hand side frame includes a front leg 36, rear leg 38, and an arm 40 extending between the front leg and rear leg and formed integrally with those legs. A bracket 42, surrounding the outer surface of the front leg 36, is clamped to the front leg and joined to a forward portion of the outer surface of intermediate longitudinal arm 44 by a pin or bolt 46, which extends through the bracket 42 and arm 44. A weld 48 joins the rear of arm 44 to the rear leg 38. A stopper cap 50 covers the lower end of the front leg 36 and another cap 52 covers the lower end of rear leg 38. Each cap preferably is formed of rubber or an elastomer.

[0023] A sleeve 54 having a somewhat larger inside diameter then the outer diameter of front leg 36 is moveably supported on that front leg above the location of bracket 42 and extends upward to the location of the upper lateral arm 32, which is connected to the sleeve 54 at the left-hand lateral end, preferably by a weld 56. A lower lateral arm 60 is joined preferably by welds 69 at each of its ends to sleeves 30, 54 and is joined to the upper lateral arm 32 by a weld at 62.

[0024] FIG. 2 shows a detail of the left-hand side frame having the side frame in the fully open or in-use position. The detail of FIG. 2 is substantially identical to the corresponding area at the right-hand side frame.

[0025] A helical coiled compression spring 68 surrounds front leg 36 and is fitted in a space between the upper surface 70 of bracket 42 and the lower surface 72 of sleeve 54. Spring 68 continually urges sleeve 54 upward toward arm 40 and away from bracket 42, yet the spring permits the sleeve to move downward against the force of the spring when a downward load is applied to a sleeve 30, 54 or to either or both lateral arms 32, 60.

[0026] Front leg 36 carries a detent pin 74 that extends radially outward in diametrically opposite directions from the outer surface of leg 36. A portion of the length of pin 74 near each of its ends becomes seated in and thereby engages substantially semicircular, diametrically opposite recesses 76, 78, formed through the thickness of sleeve 54 on an arcuate planar portion of the upper surface of sleeve 54.

[0027] FIG. 3 is a top end view of the sleeve 54 that shows recesses 76, 78 and a several similar diametrically opposite recess pairs 80, 82 and 84, 86, which are mutually spaced angularly and distributed around the portion 75 of the upper surface of sleeve 54. Pin 74 extends radially outward in diametrically opposite directions from the surface of frame 40 a distance long enough in each direction to engage each member of the recess pairs.

[0028] The upper surface of sleeve 54 is also formed with a substantially planar arcuate surface 90, which extends angularly about the axis of sleeve 54 a portion of the circumference of the sleeve. Surface 90 preferably faces laterally inward from the sleeve, and surface 75, another substantially planar arcuate surface, faces laterally outward from sleeve 54. An angular end of surface 90 includes a stop surface or step 92, which extends parallel to the longitudinal axis of sleeve 54 to the surface of recess 76, and another stop surface or step 94 extends parallel to the axis of the sleeve to the surface of recess 86.

[0029] Stop surfaces 92, 94 limit the range of angular movement of the front and rear legs 36, 38 relative to sleeve 54. Surface 92 is located so that pin 74 contacts stop surface 92 when the frame is fully opened to the in-use position, the position of FIGS. 2 and 5. Stop 92 also guides movement of the sleeve 54 relative to pin 74 as the sleeve slides upward relative to leg 36 when downward force is removed from the sleeves and cross members 32, 60 after the walker is opened. Engagement of pin 74 in recesses 76, 78 locks the walker in the opened, in-use position.

[0030] Surface 94 is located so that pin 74 contacts stop surface 94 when the frame is fully closed, the position of FIG. 6. Stop 92 also guides movement of the sleeve 54 relative to pin 74 as the sleeve slides upward when downward force is removed from the sleeves and cross members 32, 60 after the walker is folded. Engagement of the pin 74 in recesses 84, 86 locks the walker in the folded position.

[0031] In operation, the walker can be locked in the fully opened position of FIGS. 2 and 5 by forcing lateral arms 32, 60 downward thereby the depressing the sleeves 30, 54 against the upward forces of springs 68, rotating legs 12, 36 about the axes of sleeves 30, 54 until pins 74 contact the respective stops 92, releasing downward force from the lateral arms, allowing the sleeves to move upward due to the forces of the springs, and allowing pins 74 to engage the recess pairs 76, 78 at the left-hand and right-hand sleeves 30,54.

[0032] The walker can be locked in the fully-closed or folded position of FIG. 6 by forcing lateral arms 32, 60 downward thereby the depressing sleeves 30, 54 against the upward forces of the springs 68, rotating legs 12, 36 about the axes of sleeves 30, 54 until the pin 74 contacts stop 94, releasing the sleeves, allowing them to move upward due to the forces of the springs, and allowing pin 74 to engage the recess pairs 84, 86 at the left-hand and right-hand sleeves 30,54.

[0033] The walker can be locked in several partially folded positions by depressing sleeves 30, 54 against the upward forces of the springs 68, rotating legs 12, 36 about the axes of sleeves 30, 54, respectively, releasing the sleeves and allowing them to move upward due to the forces of the springs, and allowing pin 74 to engage any of the intermediate recess pairs, such as recess pairs 80, 82 at the left-hand and right-hand sleeves 30,54.

[0034] FIG. 7 shows sleeve 54 replaced by sleeve 100, which is identical to sleeve 54 except that the recesses and blocking surfaces at the upper end of the sleeve 54 are removed and replaced by radially directed holes 102, 104, which are spaced mutually around the circumference of sleeve 100. Sleeve 100 is fixed against rotary and linear displacement relative to the frame, preferably at bracket 42, and the spring 68 is removed. Each hole 102, 104 can be brought into alignment with a radial hole 106 formed in each front leg 36′ by rotating the leg within the sleeve. A detent button 108, biased by a compression spring 110 into engagement with holes 102, 104, 106, is forced from engagement with the holes by a pulling force manually applied to a cable 112 or another tension member. The button is prevent from falling through the holes due to contact between the outer surface of sleeve 100 and flange 114, formed on the button. When hole 106 is aligned with hole 102 and cable 112 is released, button 108 protrudes into the holes and fixes the rotary position of the leg in relation to the sleeve so that the leg is locked in the in-use position. To fold the device, the cable is pulled rightward against the force of spring 110, button 108 disengages the holes, leg 36′ is turned in the sleeve 100 until hole 104 aligns with hole 106, the cable is released, and the button engages holes 106 and 104, thereby locking leg 36′ and sleeve 100 in the folded position.

[0035] FIG. 8 shows sleeve 54 replaced by sleeve 120, which is identical to sleeve 54 except that the recesses and blocking surfaces at the upper end of the sleeve 54 are removed and replaced by radially directed holes 102, 104 spaced mutually around the circumference of the sleeve 120. Also sleeve 100 is fixed against rotary and linear displacement to the frame, preferably at bracket 42, and spring 68 is removed. Each hole 102, 104 can be brought into alignment with a radial hole 106 formed in each front leg 36′ by rotating the leg within the sleeve. A detent button 122, biased by bending of a spring clip 124 into engagement with holes 102, 104, 106, is forced from engagement with the holes by a pulling force manually applied to a cable 112 or another tension member. Clip 124, which is preferably formed of thin sheet metal, is fixed to lateral arm 32′ by a rivet or screw 126 and a tang 128 that fits in a hole on the under surface of arm 32′. When cable 112 is pulled, clip 124 bends in response to tension in the cable and the button 122 is removed from the holes. Upon release of cable tension, clip 124 returns elastically to the position of FIG. 8. The button is prevented from falling through the holes due to contact between the adjacent outer surfaces of sleeve 120 and clip 124.

[0036] When hole 106 is aligned with hole 102 and cable 112 is released, button 108 protrudes into the holes and fixes the rotary position of leg 36′ in relation to sleeve 120 so that the leg is locked on the sleeve in the in-use position. To fold the device, the cable is pulled rightward against the restoring force of spring clip 124, button 102 disengages the holes, leg 36′ is turned in the sleeve 120 until hole 104 aligns with hole 106, the cable is released, and the button locks the leg and sleeve in the folded position.

[0037] An alternative technique for locking the sleeves 130 that surround each front leg 12, 36 is shown in FIG. 10. Bracket 42 supports compression spring 68, which continually urges sleeve 130 upward, yet allows the sleeve to move downward against the spring force when a downward force is applied to the sleeve or the lateral arms 32, 60, to which the sleeve is attached. Sleeve is prevented from rotating relative to leg 36 because the lateral arms 32, 60 are mutually fixed to sleeve 130 and its corresponding sleeve at the opposite side frame, which sleeves surround front legs of each of the side frames. The front leg 36 passes through the length of the sleeve 130. The uppermost surface of sleeve 130 is formed with detent dog teeth 132, a series of alternate peaks and valleys that extend around the circular upper end of the sleeve. Each front leg 12, 36 carries a collar 134 having a detent in the form of dog teeth 136 complementary to teeth 132, also in the form of a series of alternate peaks and valleys that extend around the circular upper end of the collar. The collar is fixed against rotary and linear displacement with respect to the front leg. The teeth of the collar and those of the sleeve are adapted to engage mutually due to their form and to remain engaged due to the force of the spring. The teeth 132, 134 engage mutually whenever the spring force forces them into engaging contact regardless of the angular disposition of the front leg with respect to the sleeve. Therefore, the front legs can be locked against rotation on the sleeve at any angular position where the teeth 132, 136 engage whether the device is fully folded, fully opened, or partially folded.

[0038] Although the form of the invention shown and described here constitutes the preferred embodiment of the invention, it is not intended to illustrate all possible forms of the invention. Words used here are words of description rather than of limitation. Various changes in the form of the invention may be made without departing from the spirit and scope of the invention as disclosed. 

I claim:
 1. A foldable walker, comprising: first and second side frames spaced mutually, each side frame having a front leg, rear leg, and an arm connecting the front leg and rear leg; a lateral arm interconnecting the first and second side frames, and fixed against rotation relative to the front legs; a first sleeve fixed to the lateral arm, surrounding a portion of a first leg of a first member of a group consisting of the first side frame and second side frame, permitting rotary movement of said first leg relative thereto; first spring means for urging said first front leg and said first sleeve into releasable mutual engagement, said engagement preventing rotary movement of said first leg relative to the first sleeve.
 2. The walker of claim 1, further comprising: a second sleeve fixed to the lateral arm, surrounding a portion of a second leg of the second member of said group, permitting rotary movement of said second leg relative thereto; second spring means for urging said second front leg and said second sleeve into releasable mutual engagement, said engagement preventing rotary movement of said second leg relative to the second sleeve.
 3. The walker of claim 1 wherein: the first sleeve carries a first detent; the first leg further comprises a first surface adapted for engagement with a first detent; and the first spring means comprises a spring continually urging the first sleeve to move the detent along said first leg into engagement with said first leg.
 4. The walker of claim 3 wherein the first sleeve includes first teeth, and said first leg includes carries second teeth complementary to the first teeth and adapted to releaseably engage the first teeth in response to a force produced by the spring.
 5. The walker of claim 1 wherein the first sleeve is formed with a first hole, the first leg has second holes spaced mutually around a longitudinal axis of the first leg, each second hole arranged to align with the first hole, further comprising: a first detent adapted to releasably engage the first hole and a second hole; and the first spring means comprises a spring continually urging the first detent into engagement with the first hole and a second hole; and means for moving the first detent against the spring out of said engagement.
 6. The walker of claim 1 wherein the first sleeve is formed with a first hole, the first leg has second holes spaced mutually around a longitudinal axis of the first leg, each second hole arranged to align with the first hole, further comprising: a second detent adapted to releasably engage the first hole and a second hole; and the first spring means comprises a spring clip supported on the lateral arm, carrying the second detent, elastically urging the second detent into engagement with the first hole and a second hole; and means for elastically bending the spring clip away from said first sleeve, whereby second detent moves out of said engagement.
 7. A walker able to be opened for use and folded, comprising: first and second side frames spaced mutually, each side frame having a front leg, rear leg, and an arm connecting the front leg and rear leg; a first pin carried on and extending from a first front leg of one of the group consisting of the first side frame and second side frame; a first sleeve surrounding a portion of said first front leg, having a first recess adapted to engage said pin, said engagement preventing displacement of the leg relative to the first sleeve; a first spring urging the first recess and first pin into mutual engagement; a second pin carried on and extending from a second front leg; a second sleeve surrounding a portion of said second front leg, having a second recess adapted to engage said pin, said engagement preventing displacement of the leg relative to the second sleeve; a second spring urging the second recess and second pin into mutual engagement; and a lateral arm mutually connecting the first sleeve and second sleeve, preventing rotation of the first sleeve relative to the second sleeve and requiring coordinated linear displacement of the first sleeve and second sleeve.
 8. The walker of claim 7, wherein the first pin is located angularly about a longitudinal axis of the first leg and is directed radially in opposite directions from the first front leg; the second pin is located angularly about a longitudinal axis of the second leg and is directed radially in opposite directions from the second front leg; and further comprising: first recess pairs formed on the first leg, each pair of said first recess pairs being spaced angularly about a longitudinal axis of the first leg, each recess member of a pair of said first recess pairs being aligned diametrically opposite the corresponding recess member of said pair, each first recess pair being adapted for engagement with the first pin, said first recess being a member of a pair of said first recess pairs; and second recess pairs formed on the second leg, each pair of said second recess pairs being spaced angularly about a longitudinal axis of the second leg, each recess member of a pair of said second recess pairs being aligned diametrically opposite the corresponding recess member of said pair, each second recess pair being adapted for engagement with the second pin, said second recess being a member of a pair of said second recess pairs.
 9. The walker of claim 8, further comprising: a first stop surface formed on the first front leg, located for contact with the first pin, said contact limiting angular displacement of the first side frame relative to the first sleeve; and a second stop surface formed on the second front leg, located for contact with the second pin, said contact limiting angular displacement of the second side frame relative to the second sleeve.
 10. The walker of claim 8, further comprising: a third stop surface formed on the first front leg, located for contact with the first pin, said contact limiting angular displacement of the first side frame relative to the first sleeve; and a fourth stop surface formed on the second front leg, located for contact with the second pin, said contact limiting angular displacement of the second side frame relative to the second sleeve.
 11. The walker of claim 8, further comprising: a first stop surface formed on the first front leg, located for contact with the first pin, said contact limiting angular displacement of the first side frame relative to the first sleeve; a second stop surface formed on the second front leg, located for contact with the second pin, said contact limiting angular displacement of the second side frame relative to the second sleeve; a third stop surface formed on the first front leg, located for contact with the first pin, said contact limiting angular displacement of the first side frame relative to the first sleeve; and a fourth stop surface formed on the second front leg, located for contact with the second pin, said contact limiting angular displacement of the second side frame relative to the second sleeve.
 12. The walker of claim 8, further comprising: a first stop surface formed on the first front leg, located for contact with the first pin, said contact limiting angular displacement tending to open the first side frame; and a second stop surface formed on the second front leg, located for contact with the second pin, said contact limiting angular displacement tending to open the second side frame; a third stop surface formed on the first front leg, located for contact with the first pin, said contact limiting rotation of the first front leg tending to fold the first side frame; and a fourth stop surface formed on the second front leg, located for contact with the second pin, said contact limiting rotation of the second front leg tending to fold the second side frame.
 13. The walker of claim 8, wherein: the first stop surface is located adjacent a first recess of a first recess pair; the second stop surface is located adjacent a first recess of a second recess pair; the third stop surface is located adjacent a second member of said first recess pair; and the fourth stop surface is located adjacent a second member of said second recess pair.
 14. A frame for a walker able to be opened for use and folded, comprising: a first side frame, having a front leg, rear leg, and an arm connecting the front leg and rear leg; a first pin carried on and extending from the first side frame; a first sleeve surrounding a portion of the first side frame, permitting angular displacement and linear displacement of said first side frame relative to the first sleeve, having a first recess adapted to engage said first pin, said engagement preventing displacement of the first side frame relative to the first sleeve; and a first spring urging the first recess and first pin into mutual engagement; a first stop surface formed on the first side frame, located for contact with the first pin, said contact limiting angular displacement of the first side frame in a first direction relative to the first sleeve; a second stop surface formed on the first side frame, located for contact with the first pin, said contact limiting angular displacement of the first side frame in a second direction opposite the first direction relative to the first sleeve.
 15. The frame of claim 14, further comprising: a second side frame, having a front leg, rear leg, and an arm connecting the front leg and rear leg; a second pin carried on and extending from the second side frame; a second sleeve surrounding a portion of the second side frame, permitting angular displacement and linear displacement of said second side frame relative to the second sleeve, having a second recess adapted to engage said second pin, said engagement preventing displacement of the second side frame relative to the second sleeve; and a second spring urging the second recess and second pin into mutual engagement; a lateral arm mutually connecting the first sleeve and second sleeve, preventing rotation of the first sleeve relative to the second sleeve and requiring coordinated linear displacement of the first sleeve and second sleeve; a third stop surface formed on the second side frame, located for contact with the second pin, said contact limiting angular displacement of the second side frame in a first direction relative to the second sleeve; a fourth stop surface formed on the second side frame, located for contact with the second pin, said contact limiting angular displacement of the second side frame in a second direction opposite the first direction relative to the second sleeve.
 16. A frame for a walker able to be opened for use and folded, comprising: a first side frame, having a front leg, rear leg, and an arm connecting the front leg and rear leg; a first sleeve surrounding a portion of the first side frame, adapted to engage the first side frame against rotary displacement of the first side frame relative to the first sleeve; and spring means for resiliently urging mutual engagement of the first sleeve and first side frame the first recess and first pin into mutual engagement; a first stop surface formed on the first side frame, located for contact with the first pin, said contact limiting angular displacement of the first side frame in a first direction relative to the first sleeve; a second stop surface formed on the first side frame, located for contact with the first pin, said contact limiting angular displacement of the first side frame in a second direction opposite the first direction relative to the first sleeve. 